Engine stalling can be caused by an evap problem. For example, if air isn’t being properly allowed into the tank as the gas is used up by driving, it will create an unwanted vacuum in the fuel tank, preventing adequate quantities of fuel from being delivered to the engine. Too-lean operation in other words. Likewise too much pressure build-up in the tank due to an evap problem could cause an overly rich mixture, and stalling from that.
Here’s something you can do: When you remove the fuel cap when these symptoms develop, do you hear a distinct “whish” sound? If so, a partial vacuum forming in the gas tank could be contributing to the symptoms.
If the evap code has been there for ages and the symptoms showed up only just recently, the evap issue is probably not the cause. But mechanics usually – when diagnosing difficult to solve problems – try to figure out the cause of all the diagnostic codes first. They do it that way b/c of experience. They’ve had cars with difficult to diagnose problems where if they had done it that way first, they’d have saved a lot of time, money, and grief.
Exactly what did the mechanic do for the MAF sensor? Did he just clean it, replace it with used unit, a new Chinese unit or an OEM unit.
Cleaning would be a $20-100 job, a used one ???, a new Chinese replacement would be $20-80 for the part plus install, an OEM would be $400+ plus install.
Regarding Nevada’s suggestion about checking for other fault codes you might drop by an AutoZone, Advance, O’Reillys auto parts store in your area. They will do a basic scan and provide you with any codes that are present. They will do this free of charge.
Keep in mind they provide the codes; they do NOT (and should not) provide a diagnosis. It’s free anyway…
I’m generally a glass half full guy so I tend to think most problems have a simple root cause although I’m aware that sometimes finding the root can be difficult…
For a '97 Benz at 1700 bucks I don’t think you got hurt at all and a few hiccups can be expected out of any car with a little age on it.
I would suggest having a vacuum check done it also and I believe that was mentioned previously.
A vacuum gauge check is cheap, quick, and easy and can reveal many things about what is going on inside the engine. Hope that helps.
Might want to check it out, before moving on to other things. At least rule it out, as part of the diagnosis
A fairly savvy guy with a multimeter could quickly determine if it was working correctly or not. Simple 5V reference, I believe. Electrically, it works just like a tps, I want to say
This sensor is in the engine bay. Should be between the master cylinder and the firewall
The electronic throttle body had a tendency to fail in strange ways, creating unstable idle conditions. It didn’t happen all the time, but I did replace several throttle bodies. Cleaning them didn’t help, by the way
And yes, as mentioned, the crankcase breather hoses had a tendency to get spongy and allow unmetered air
db4690 is our resident Benz expert and he got to what I was thinking, but with much more clarity and detail. I remember these cars having problematic throttle bodies. Whatever you do don’t install a used one unless you can verify 100% that it’s good.
I don’t know. My experience with these is very limited. I remember replacing a throttle body 15 years ago but it was with a new unit from the dealer and quite pricey. I don’t know how you would check one unless it was on a running car.
Wow, thank you all! I’ll keep this in mind. Mechanic called me today, and sainthood emit 100% sure it’s the issue, but there is a crack in my valve intake gasket… But it’s another $600 fix! I’m nervous to replace that if the problem end up being something else. Does it sound likely to you all? They haven’t checked the transmission (which was a possibility because of a newly discovered hesitation when stitching gears) because it’s a closed system and they’d have to do a transmission flush, another $100. I’d’ve been willing to pay it, if not for the recent $1,200 in repairs! Thanks for your collective brain power!
...but there is a crack in my valve intake gasket...
Assume you mean “…crack in my intake manifold gasket.” This should be an easy diagnosis by spraying ether or carb cleaner on the crack and having the idle change noticeably.
An air leak in any part of the intake tract can cause problems. Hopefully that diagnosis is correct and the mechanic should be able to point the problem area out to you.
There is a dipstick tube and a drain plug on the pan. As a matter of fact, the torque converter also has a drain plug
here’s the thing . . . the car has no dipstick. The mechanic has to use a special flexible dipstick, which has markings. I won’t get into the reasons, but that’s how it is on your car
I’m guessing they don’t have this tool, or for some reason assume it’s a sealed unit.
By the way, there is no such thing as a sealed transmission. Total marketing BS. And the main purpose is to make the customer think the transmission never needs servicing . . . ha ha
An evap/smoke machine would very quickly detect unmetered air. It will remove all shadow of a doubt. Because you’ll know the size of the leak, and you will physically see the smoke pouring out from the leaking component
There are other ways to find leaks, but the evap/smoke machine is fast and efficient, and shops that deal with driveability complaints should have one. They’re not that expensive, and the shop can write it off
I doubt the shop you’re taking your car to now can do this . . .
But there are scan tools out there that will display the transmission’s adaptation values. And from that data, you can pretty much figure out if it’s at the end of its useful life.
As far as servicing your transmission goes, I would opt for a simple drain and refill. Drain the torque converter and the pan. Then drop the pan, replace the filter and gasket. Your transmission is a 722.6 or NAG1, depending on who you talk to. Make sure the correct fluid is used. It doesn’t necessarily have to be from the dealer, but that would be the best way to ensure the correct fluid is used. If you go to the dealer, it’s possible you’ll get 722.9 fluid, which is backwards compatible. 722.9 is an even newer transmission
To be quite honest, I wouldn’t be surprised if the transmission is on the downward slope, so to speak, based on its age and mileage
here’s a thought . . . service the transmission now, and just keep using the car until the transmission or something else very expensive conks out and makes the car essentially undriveable
That seems like very sound advice, thank you! Is what you’re describing meaningfully different from a “transmission flush”? Safer? Riskier? I would like to have that serviced, but a flush costs another $100, and I know it’s sad, but I can’t afford even that right now. A cap gasket also has to be replaced in the future (another $600), but they said it’s lower priority and could wait a little while… Guh.
What I was describing is without a doubt much safer than a transmission flush
A transmission flush is more beneficial to the shop’s bottom line, because the pan is not removed, and the filter is not replaced
it is extremely profitable for a shop to perform a flush
But remember that with a flush, that dirty filter and rotten pan gasket won’t be replaced. And the mechanic won’t be able to clean the crud at the bottom of the pan. And he also won’t be aware of any particles at bottom of the pan
Thanks for describing that difference! I have heard that sometimes a transmission flush/change can somehow either fix, or destroy a transmission system on an older car. Scary thought! I’ll ask them how much it is to just drain and refill it.
